Siege of Niuzao Temple: Gold

Completing these Gold achievements rewards a teleport spell so you can quickly get to the instance when ever you want. These spells are fly-out spells, meaning they are grouped and only take one actionbar slot -that's nice. The fly-out group consists of:

[spell=131204]

Temple of the Jade Serpent: Gold

[spell=131205]

Stormstout Brewery: Gold

[spell=131206]

Shado-Pan Monastery: Gold

[spell=131222]

Mogu'shan Palace: Gold

[spell=131225]

Gate of the Setting Sun: Gold

[spell=131231]

Scarlet Halls: Gold

[spell=131229]

Scarlet Monastery: Gold

[spell=131232]

Scholomance: Gold

→

[spell=131228]

Siege of Niuzao Temple: Gold

The complete list (in case this gets outdated) of Gold dungeon challenge achievements can be found here.

Also, if you ever wonder what heroics you have yet to complete and unlock challenge mode for, simply paste this into the chat on your character:
/run for x,i in ipairs({6456,6470,6756,6758,6759,6760,6761,6762,6763})do local _,_,_,c,_,_,_,_,_,_,_,_,m,b=GetAchievementInfo(i)print(x,"\124cff"..(m and"00ff00C"or"ff0000Inc").."ompleted\124r",GetAchievementLink(i))end

Gold requires killing all 4 bosses and 65 enemies in less than 17:30 minutes.

The Cooldown of the teleport shares among all locations. that means if you use teleport to Shoclomance you will have 8 hours cooldown for all the others.